1. Field of the Invention
The present invention relates to a test pattern generating apparatus for generating a test pattern for evaluating whether or not data and a synchronous clock signal are transmitted normally through a bus, a communication device having a test pattern generating apparatus, and a simulator.
2. Description of the Related Art
In the case where a communication system such as a local area network (hereinafter, referred to as LAN), which is arranged by connecting a plurality of terminal devices for transmitting and receiving source data with a bus, is evaluated, it is necessary to confirm whether or not source data and a waveform of a synchronous clock signal are transmitted normally through a bus.
An evaluation system for making an evaluation of the communication system is, as shown in FIG. 1, for example, composed of a simulator 51, a terminal unit 53 and an analyzer 55. In a communication system between the simulator 51 and terminal unit 53, as shown in FIG. 2, when a synchronous clock signal in the simulator 51 is changed from negative to positive (timing A), a control command is transmitted from the simulator 51 to the terminal unit 53.
Next, when the synchronous clock signal is changed from positive to negative (timing B), the simulator 51 receives a response command from the terminal unit 53 and displays the received response command on the analyzer 55. When such a process is repeated, the synchronization of the command level can be confirmed.
However, in the conventional evaluation system, only the synchronization of the command level was confirmed, and the synchronization of source data and bit synchronous clock signal was not confirmed. Moreover, even if the source data and bit synchronous clock signal were tried on a measuring apparatus, since the source data had no regularity, it was difficult to confirm the synchronization of the communication system from the source data and bit synchronous clock signal.